You need to ensure that users use multi-factor authentication (MFA) when connecting to an Azure SQL database. Which type of authentication should you use?

Azure Active Directory (Azure AD) authentication is the only method that supports modern authentication features, including Multi-Factor Authentication (MFA), for Azure SQL Database. By configuring the database to use Azure AD for authentication, you can centrally manage user identities and enforce security policies like MFA through Conditional Access. This leverages Azure AD's robust security infrastructure to protect database access, requiring users to provide additional verification beyond just a password when they connect.

A. service principal authentication: Service principals are non-interactive identities used by applications or services, not human users. MFA is designed for user sign-ins.
C. SQL authentication: This is a traditional username and password method managed within the database itself. It does not integrate with Azure AD and lacks support for MFA.
D. certificate authentication: While Azure AD supports certificate-based authentication as a factor, it is not the primary authentication type for Azure SQL Database that enables MFA. The overarching framework required is Azure AD authentication.

1. Microsoft Docs, "Multi-factor authentication for Azure SQL Database and Azure Synapse Analytics": This document explicitly states, "Azure SQL Database, Azure SQL Managed Instance, and Azure Synapse Analytics support connections from SQL Server Management Studio (SSMS) using Azure Active Directory Universal Authentication." It further clarifies that this authentication method supports MFA.

Source: Microsoft Learn, Azure SQL Database Documentation. Section: "Azure AD multi-factor authentication".

2. Microsoft Docs, "Use Azure Active Directory multi-factor authentication": This page details the prerequisites and configuration steps. It states, "Azure AD MFA with Azure SQL Database requires the use of an interactive authentication method...". The interactive methods listed are all variations of Azure AD authentication.

Source: Microsoft Learn, Azure SQL Database Security Documentation. Section: "Prerequisites".

3. Microsoft Docs, "Azure Active Directory authentication for SQL Server": This document outlines the benefits of using Azure AD authentication, including "It provides an alternative to SQL Server authentication" and enables features like MFA.

Source: Microsoft Learn, SQL Server Documentation. Section: "Benefits".